some one asked about pencil marks How to remove them. Had you thought of using a eraser. I did try using one that architect use. they use one that does not leave smear. I did use one and it did remove the pencil mark.the one i have is STAEDTLERMARS TECHNIPLAST. and it is old a fresh one could do a better job. at least it is worth a try.

seems to me I have used a "artists" or a " soft gum eraser" eraser before... it worked well too

I remember those Art Erasers... They are kinda of a off white aren't they?

I suddenly had an ah ha moment. I think I am going to make up a mock square and try my marking pens on them and the erasers to see how best to remove each one. Duhh... After all these years.

thanks, that's so good to know.